全文获取类型
收费全文 | 1025篇 |
免费 | 53篇 |
专业分类
电工技术 | 7篇 |
综合类 | 2篇 |
化学工业 | 216篇 |
金属工艺 | 30篇 |
机械仪表 | 22篇 |
建筑科学 | 54篇 |
矿业工程 | 2篇 |
能源动力 | 21篇 |
轻工业 | 160篇 |
水利工程 | 2篇 |
无线电 | 82篇 |
一般工业技术 | 207篇 |
冶金工业 | 84篇 |
原子能技术 | 10篇 |
自动化技术 | 179篇 |
出版年
2023年 | 20篇 |
2022年 | 18篇 |
2021年 | 23篇 |
2020年 | 20篇 |
2019年 | 21篇 |
2018年 | 16篇 |
2017年 | 20篇 |
2016年 | 35篇 |
2015年 | 19篇 |
2014年 | 40篇 |
2013年 | 50篇 |
2012年 | 42篇 |
2011年 | 54篇 |
2010年 | 70篇 |
2009年 | 59篇 |
2008年 | 54篇 |
2007年 | 56篇 |
2006年 | 28篇 |
2005年 | 33篇 |
2004年 | 37篇 |
2003年 | 26篇 |
2002年 | 14篇 |
2001年 | 17篇 |
2000年 | 19篇 |
1999年 | 20篇 |
1998年 | 18篇 |
1997年 | 19篇 |
1996年 | 17篇 |
1995年 | 5篇 |
1994年 | 9篇 |
1993年 | 9篇 |
1992年 | 15篇 |
1991年 | 15篇 |
1990年 | 13篇 |
1989年 | 7篇 |
1988年 | 12篇 |
1987年 | 12篇 |
1986年 | 10篇 |
1983年 | 7篇 |
1982年 | 12篇 |
1981年 | 7篇 |
1980年 | 10篇 |
1979年 | 8篇 |
1978年 | 8篇 |
1977年 | 6篇 |
1976年 | 7篇 |
1974年 | 11篇 |
1973年 | 4篇 |
1972年 | 5篇 |
1966年 | 3篇 |
排序方式: 共有1078条查询结果,搜索用时 31 毫秒
71.
For the first time, ion mobility spectrometers (IMS) with radioactive and UV ionization sources in combination with multicapillary columns (MCCs) have been used to determine methyl tert-butyl ether (MTBE), a gasoline additive, in water and nitrogen as well as the monoaromatic compounds benzene, toluene, and m-xylene (BTX). A membrane extraction unit was set up to extract the substances from water, which is simple, effective, and easy to automate for further applications. Thus, the detection of MTBE and BTX of gasoline vapors was accomplished after a preliminary silicone membrane extraction. Two-dimensional data analyses of IMS-chromatograms allow us to separate these substances clearly according to their different retention and drift times. Method detection limits for MTBE were 2 microg/L (UV) and 30 pg/L (63Ni) in nitrogen and 20 mg/L (UV) and 1 microg/L (63Ni) in water. Rather a good reproducibility was achieved with relative standard deviations of between 2.9 and 9%. The method presented in this article has been proven to be suitable for nearly real-time monitoring as the total analysis time is less than 90 s. As an example of application, the detection of MTBE and BTX in a mixture of volatile organic compounds of pure gasoline using the 2-D IMS-chromatogram is presented. 相似文献
72.
Georg Borges Carl-Friedrich Stuckenberg Christoph Wegener 《Datenschutz und Datensicherheit - DuD》2007,31(4):275-278
Die Autoren setzen sich mit dem Gesetzentwurf zur Bek?mpfung der Computerkriminalit?t auseinander, insbesondere mit der Strafbarkeit
des Einsatzes von Analysetools. 相似文献
73.
M. Hermatschweiler A. Ledermann G. A. Ozin M. Wegener G. von Freymann 《Advanced functional materials》2007,17(14):2273-2277
Silicon inverse woodpile photonic crystals are fabricated for the first time. Our approach, which is based on direct laser writing of polymeric templates and a novel silicon single‐inversion procedure, leads to high‐quality structures with gap/midgap ratios of 14.2 %, centered at a wavelength of 2.5 μm. It is shown that gap/midgap ratios as large as 20.5 %, centered at 1.55 μm, may become possible in the future. 相似文献
74.
Günter Mistlberger Klaus Koren Elisabeth Scheucher Daniel Aigner Sergey M. Borisov Armin Zankel Peter Pölt Ingo Klimant 《Advanced functional materials》2010,20(11):1842-1851
Magnetic optical sensor particles with multifunctional cores and shells are synthesized via a facile nanoprecipitation method and the subsequent modification of the particle shell. The hydrophobic particle core includes optical oxygen indicators, a light harvesting system, photosensitizers, and magnetic nanoparticles. Further functionalities are introduced by modifying the shell with enzymes, antibodies, multiple layers of polyelectrolytes, stimuli‐responsive polymers, and luminescent indicator dyes. The hydrodynamic diameter is tunable by varying different precipitation parameters. 相似文献
75.
This paper explores detailed public attitudes regarding the expanding range of biofuels technologies and policy options. Subjects from 34 in-depth focus groups in central Indiana were fairly knowledgeable about biofuels technologies, but uninformed about biofuels policies despite being from a state where biofuels are a salient political issue. A narrow majority was supportive of biofuels in general, but expressed greater enthusiasm about “second generation” biofuels. Subject beliefs about biofuels’ economic and environmental impacts were most important in shaping these opinions, rather than concerns about energy independence or other issues. In terms of policy options, subjects were most supportive of an alternative fuels standard and least supportive of a fixed subsidy and a cap and trade policy. In contrast to arguments about technologies, participants primarily framed their attitudes toward policies in terms of fairness. Although discussion did not substantially change aggregate preferences for most policies, it did increase support significantly for at least one policy proposal—a variable subsidy for ethanol. It is particularly noteworthy that subjects generally did not support the most common biofuel technology—corn-based ethanol—or the most prominent biofuels policy option—the fixed subsidy—despite residing in a state hosting a strong corn industry and staunch political advocates for both positions. 相似文献
76.
G. Von Freymann CH. Adelmann G. Scheiber TH. Schimmel & M. Wegener 《Journal of microscopy》1999,194(2-3):491-494
The depolarization near-field scanning optical microscope allows for sub-wavelength optical resolution with uncoated optical fibre tips. We show by a simple thought experiment, by numerical solution of the Maxwell equations for a realistic geometry, and by direct experiments, that this novel apparatus images gradients of the dielectric function of a sample in the direction of the incident electric field vector. The near-field images obtained from experiment and theory agree well. 相似文献
77.
Michael Beetz Freek Stulp Piotr Esden-Tempski Andreas Fedrizzi Ulrich Klank Ingo Kresse Alexis Maldonado Federico Ruiz 《Autonomous Robots》2010,28(1):21-44
This article investigates methods for achieving more general manipulation capabilities for mobile manipulation platforms,
which produce legible behavior in human living environments. To achieve generality and legibility, we combine two control
mechanisms. First of all, experience- and observation-based learning of skills is applied to routine tasks, so that the repetitive and stereotypical character of everyday activity is exploited. Second, we use planning, reasoning,
and search for novel tasks which have no stereotypical solution. We apply these ideas to the learning and use of action-related places, to the model-based
visual recognition and localization of objects, and the learning and application of reaching strategies and motions from humans.
We demonstrate the integration of these mechanisms into a single low-level control system for autonomous manipulation platforms. 相似文献
78.
79.
Nicolas Vogel Mathieu Jung Noelia L. Bocchio Markus Retsch Maximilian Kreiter Ingo Köper 《Small (Weinheim an der Bergstrasse, Germany)》2010,6(1):104-109
Nanoparticle arrays created by nanosphere lithography are widely used in sensing applications since their localized surface plasmon resonances are extremely sensitive to changes in the local dielectric environment. A major drawback for any biologically oriented sensing application of conventionally produced particle arrays is the lack of stability of the nanoparticles in aqueous media and buffer solutions. Here, a robust and reusable nanoscale sensing platform based on localized surface plasmon resonances of gold nanoparticles embedded in a silicon dioxide matrix is presented. The architecture exhibits extremely high stability in aqueous environments and can be regenerated several times by simple mechanical cleaning of the surface. The platforms surface is ultraflat by design, thus making it an ideal substrate for any bio‐oriented sensing application. 相似文献
80.
Substitution von Torf durch Holz in Pflanzsubstraten 总被引:1,自引:1,他引:0
Ohne Zusammenfassung 相似文献